Results 1 to 5 of 5
Like Tree1Likes
  • 1 Post By Ozman13

Thread: Questions about field of view generally.

  1. #1
    harryhh's Avatar
    harryhh is offline Main Sequence
    Points: 1,380, Level: 21
    Level completed: 80%, Points required for next Level: 20
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!Ghost Achievement! Averaging 5+ posts a day!
    Join Date
    Jun 2017
    Location
    Northcentral Illinois
    Posts
    168
    Points
    1,380
    Level
    21
    Thanks
    0
    Thanked 12x 4 Posts

    Default Questions about field of view generally.



    If I understand it correctly, there are a number of factors that determine the FOV of a telescope. But, do I have this right? Generally, a refractor has a wider FOV than a Cassegrain, which has a wider FOV than a Mak? Meaning the Mak generally has the least FOV of these three scopes.

    Harry
    Orion Apex 102mm Mak, Celestron 6x30 finder, Orion 90* prism diagonal, 45* erecting prism diagonal, Celestron straight through porro prism, Tele Vue 1.8x Barlow, 25mm 52* Super Plossl eyepiece, SVBONY 23mm 62* Aspheric eyepiece, 8.5mm Konig eyepiece

  2. #2
    Ozman13's Avatar
    Ozman13 is online now HYPER GIANT
    Points: 28,013, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 99.7%
    Achievements:
    2 Posts Achievement5 Threads Achievement!20 Posts Achievement!365 Days+ Registered Achievement!50 Posts Achievement!
    Awards:
    3rd Most Active Award
    Join Date
    Jun 2013
    Location
    Hopkinsville Kentucky
    Posts
    8,087
    Points
    28,013
    Level
    100
    Thanks
    164
    Thanked 2,151x 1,930 Posts

    Default Re: Questions about field of view generally.

    Generally speaking, the longer the focal length of the scope, the narrower the field of view.

    A Mak and an SCT are both cassegrain scopes. Because they both reflect the light back and forth in the tube, they have long focal lengths and narrow field of view.
    Testgear likes this.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ACF 8"SCT,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    ,
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    120, ES 102CF Apo triplet, ES AR102, ST100, ST90, Apex 90mm Mak, ST80, ETX60,
    Oberwerk 25x100s, 15x70s, 8x56s, Kasai 2.3x40s, Celestron AVX, CG4, SLT, LCM, Obie HD Parallel Bino mount
    Explore Scientific 82 degree and 68 degree EPs, Baader 9mm Ortho, Meade 5000 SWA EP set, many more various EPs, Baader
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    &SkyGlow, FringeKiller, SemiApo filters, Celestron UHC, Meade 4000 Nebular Filter, Kson OIII, DGM NPB and lots of astro stuff.

  3. The Following User Says Thank You to Ozman13 For This Useful Post:

    michael131313 (06-26-2017)

  4. #3
    Gabby76's Avatar
    Gabby76 is offline Super Moderator
    Points: 80,899, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 74.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!Gallery Achievement!Album Achievement!50 Posts Achievement!
    Awards:
    Activity & Post & Thread Master
    Join Date
    Jan 2016
    Location
    Live: Slovakia Work: Canada
    Posts
    18,728
    Points
    80,899
    Level
    100
    Thanks
    3,590
    Thanked 5,886x 4,936 Posts
    Blog Entries
    4

    Default Re: Questions about field of view generally.

    Typically SCTs are f/10 and Maks are f/13- f/15 so they have the narrowest field of view of the three designs.
    Refractors: Antares 105 f/15, Celestron 150 f/8, Stellarvue NHNG 80 f/6.9, TAL 100RS f/10, TS 102 f/11, UR 70 f/10, Vixen SD115s f/7.7
    Mounts: Celestron SLT w/ pier mod & EQ-3 tripod, Celestron hypertuned CG-5 w/ tracking motor & Argo Navis, Manfrotto 028B w/ Stellarvue M2C, Manfrotto 055PRO w/ 128RC, TAL-1 HD EQ, Vixen SXP w/ HAL-130 SXG & half pier Diagonals: 2" Astro-Physics MaxBright, 2" Zeiss/ Baader prism, 2" Baader Herschel Wedge (Photo Version), 2"
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Amici prism, 2" Stellarvue Dielectric, 2" TeleVue Everbrite Eyepieces: A-Z

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    The weakest link in the optical chain is the large nut located directly behind the
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    / camera. - Gabrielle

    Ya gotta keep this Apo/
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    thing in some balance of perspective. Apos are awesome, but long focus Achros aren't that far behind them - Siriusandthepup (CN)

    Refractors kick arse precisely because they don't hide behind excuses. That is, they have no obstructions to hide behind. - Jon Isaacs (CN)

  5. The Following User Says Thank You to Gabby76 For This Useful Post:

    michael131313 (06-26-2017)

  6. #4
    harryhh's Avatar
    harryhh is offline Main Sequence
    Points: 1,380, Level: 21
    Level completed: 80%, Points required for next Level: 20
    Overall activity: 0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!5 Threads Achievement!50 Posts Achievement!Ghost Achievement! Averaging 5+ posts a day!
    Join Date
    Jun 2017
    Location
    Northcentral Illinois
    Posts
    168
    Points
    1,380
    Level
    21
    Thanks
    0
    Thanked 12x 4 Posts

    Default Re: Questions about field of view generally.

    Thank you folks.

    Generally, some of the short tube refractors that I have been looking at have f/7 to f/5. So, apparently, a refractor of that focal ratio would have a noticeably wider field of view over the SCT and Mak.

    Is that correct?

    Harry
    Orion Apex 102mm Mak, Celestron 6x30 finder, Orion 90* prism diagonal, 45* erecting prism diagonal, Celestron straight through porro prism, Tele Vue 1.8x Barlow, 25mm 52* Super Plossl eyepiece, SVBONY 23mm 62* Aspheric eyepiece, 8.5mm Konig eyepiece

  7. #5
    Gabby76's Avatar
    Gabby76 is offline Super Moderator
    Points: 80,899, Level: 100
    Level completed: 0%, Points required for next Level: 0
    Overall activity: 74.0%
    Achievements:
    2 Posts Achievement20 Posts Achievement!Gallery Achievement!Album Achievement!50 Posts Achievement!
    Awards:
    Activity & Post & Thread Master
    Join Date
    Jan 2016
    Location
    Live: Slovakia Work: Canada
    Posts
    18,728
    Points
    80,899
    Level
    100
    Thanks
    3,590
    Thanked 5,886x 4,936 Posts
    Blog Entries
    4

    Default Re: Questions about field of view generally.

    Yes that is correct
    Refractors: Antares 105 f/15, Celestron 150 f/8, Stellarvue NHNG 80 f/6.9, TAL 100RS f/10, TS 102 f/11, UR 70 f/10, Vixen SD115s f/7.7
    Mounts: Celestron SLT w/ pier mod & EQ-3 tripod, Celestron hypertuned CG-5 w/ tracking motor & Argo Navis, Manfrotto 028B w/ Stellarvue M2C, Manfrotto 055PRO w/ 128RC, TAL-1 HD EQ, Vixen SXP w/ HAL-130 SXG & half pier Diagonals: 2" Astro-Physics MaxBright, 2" Zeiss/ Baader prism, 2" Baader Herschel Wedge (Photo Version), 2"
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    Amici prism, 2" Stellarvue Dielectric, 2" TeleVue Everbrite Eyepieces: A-Z

    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.

    The weakest link in the optical chain is the large nut located directly behind the
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    / camera. - Gabrielle

    Ya gotta keep this Apo/
    To view links or images in signatures your post count must be 5 or greater. You currently have 0 signatures.
    thing in some balance of perspective. Apos are awesome, but long focus Achros aren't that far behind them - Siriusandthepup (CN)

    Refractors kick arse precisely because they don't hide behind excuses. That is, they have no obstructions to hide behind. - Jon Isaacs (CN)

 

 

Similar Threads

  1. Field of view
    By robertosol in forum Astronomy Beginners Forum
    Replies: 4
    Last Post: 12-07-2011, 08:34 AM
  2. Field of View
    By GWING in forum Telescope Eyepieces Forum
    Replies: 4
    Last Post: 08-08-2011, 10:58 PM
  3. Field of View
    By Zorrosuncle in forum Astronomy Beginners Forum
    Replies: 2
    Last Post: 04-03-2011, 11:20 PM
  4. Best Field of view??
    By Heirwalker in forum Astronomy Beginners Forum
    Replies: 17
    Last Post: 06-22-2010, 06:15 PM
  5. Field of view
    By Martin Anderson in forum UK Astronomy Forum
    Replies: 8
    Last Post: 09-17-2003, 06:26 AM

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
Powered by vBulletin® Version 4.2.0
Powered by vBulletin®
All times are GMT. The time now is 10:09 PM.